Electric crane



w. RICHTER ELECTRIC CRANE Dec. l, 1931.

2 Sheets-Sheet' 1 Filed June 13, 1930 ATTORNEY,

Dec. 1, 1931.

W. RICHTER ELECTRIC CRANE Filed June 13, l

I N VEN TOR.

Half/1er Rich fer' 2 Sheets-Sheet 2 A TTORNE Y.

Patented Dec. 1, 1931 UNITED STATES PATENT OFFICE WALTHEB. RICHTER, 0F MILWAUKEE, WISCONSIN, ASSIGNOR TO A. 0. SEMITH COR- PORATION, OF MILWAUKEE, WISCONSIN, A CORPORATION 0F NEW YORK ELECTRIC CRANE Application 1ed `Tune 13,

The present invention relates to electric cranes. i

An object of the invention is to provide an electric crane of novel construction for lifting and carrying rigid members such as pipe.

A further object is to provide an electric crane embodying means for preventing lifting before the load is safely secured.

The invention will be best understood by referring to the accompanying drawings in which:

Figure 1 is a front elevation of the crane.

Fig. 2 is a front view of a unit showing the lifting'hook in alternate positions.

Fig. 3 is an end view of a unit.

Fig. 4 is a. front View of the switch and means for operating the same.

.The crane comprises in general two parts, the carriage 1 and the boom 2. The carriage 1 may be of the-conventional type running on rails in substantially the same horizontal plane,l and supporting the control mechanism, the driving and lifting motors, the operator, and the boom. The boom 2 may be suspended from the carriage 1 by cables 3, chains, or the like, andA is adapted to remain in a horizontal position and to be raised and lowered by means of the cables 3 by which it is suspended.

The embodiment described herein is adapted to lift and `carry rigid tubular members such 'as oil line pipe. The boom 2 is preferably formed of beams 4 of structural steel, and has a length substantially that of the longest pipe to be handled.

One unit 5 of the hooking and releasing mechanism is stationed at each end of the boom. Each unit 5 is bolted, riveted, welded or otherwise firmly secured to the beams 4 and, as shown in Fig. 2, is provided with a hook 6 which preferably has bracing members 7, disposed across a portion of the hook and welded in place, to counteract the tendency of the hook to straighten out and drop its load.

The hook 6 is connected at its upper eXtremity to a solenoid 8 by means of a link 9. Pins 10 and 11 secure the link to the respective parts.

The hook 6 is pivoted intermediate the 1930. serial-No. 460,937. y

linked upper end and the hooked lower end, the pivot l2 being preferably nearer the linked end. Inasmuch as the solenoid 8 is provided merely to move the hook 6 out of engagement with the pipe 13, little power is needed to accomplish the result, and the pivot 12 is so placed as to give an exaggerated motion to the hooked end to insure proper clearance beyond the end of the pipe. Hence a short stroke of the solenoid 8 produces a long stroke on the curved end of the hook 6.

A bumper 14 is welded to the ends of the beams 4, extending outwardly toward the hook 6, and is adapted to arresty movement of said hook when the solenoid 8 is rie-energized.

The safety device comprising one of the features of the present invention is a switch 15 adapted to break the circuit of the lifting motor when the hook 6 is not completely open or closed, thereby preventing lifting of the boom before the load is safely secured or entirely released by the hooks 6. The switch l5 has an arm 16 having a roller 17 disposed at its outer end. The roller 17 is adapted toy be engaged by the cam face 19 of an arm 18 which is welded or otherwise attached to the hook 6. The cam face 19 is provided with a depression 20 and rises 21 and 22. When the hook 6 is completely open the roller 17 will engage the cam rise 21 and when completely closed it will engage the cam rise 22 thus maintaining the switch 15 closed when the hook is in completely open or closed position.. If, however, in picking up or releasing a load the hooks 6 are not completely closed or opened, the roller 17 will lie in the depression 2() of the cam face 19 thus causing a break in the lifting motor circuit and rendering the motor inoperative.

In operation, the boom 2 is lowered over the pipe 13 to be lifted. T-he solenoids 8 are then energized and the hooks 6 lifted outwardly away from each other. When the boom 2 is properly aligned, the solenoids 8 are de-energize'd. The hooks 6 drop by their own weight into the ends of the pipe 13, or beneath the load to be lifted, falling into engagement with the bumper 14. At this position the switch arm 16 has been tripped and the safety switch 15 for the lifting motor closed, enabling the operator to close the cir cuit from the control booth and to cause the pipe 13 to be lifted and transported at will. In releasing a pipe the boom is lowered to deposit the pipe in the desired position whereupon the solenoids 8 are energized to open the hooks 6. During opening of the hooks the roller 17 rides along the cam face 19 from the rise 22, through depression 20 to cam rise 21 thuscausing first an opening and then a closing of switch 15. With the hooks in completely open position the boom may be raised and the cycle o operations repeated.

I claim:

1. In a lifting crane, a horizontal boom adapted to move vertically, an independent unit at each end of said boom comprising a hook adapted to engage and release the load to be carried, means for operating the same, and means associated with each unit ladaplted to forestall vertical movement of the oom until said hook is completely engaged with or disengaged from the load.

2. In a crane for lifting and transporting pipe, a horizontal boom of substantially the length of the pipe, an independent engaging and releasing unit at each end of the boom comprising a hook adapted to enter the end of the pipe, electromagnetic means for operating the same, and means associated with each .unit adapted to prevent ver tical movement of theboom until said hook is completely engaged with or disengaged from the pipe.

8. In a crane for transporting pipe, a horizontal boom, and an independent engaging and releasing unit at each end of the boom comprising a hook pivoted intermediate its ends, a solenoid for causing said hook to 'pivot outwardly and disengage the pipe when energized and to release said hook allowing it to fall into engagement with the for preventing vertical movement of the boom until said hook is completely engaged with or disengaged from said pipe.-

6. In a lifting crane, a vertically movable boom, a hook adjacent each end of said boom adapted to engage and release the load to be carried, means for actuating said hooks, and means associated with said. actuating means for preventing vertical movement of the boom until said hooks are completely engaged with or disengaged from said load.

In witness whereof I have signed my name at Milwaukee, Wisconsin, this 11th day of June, 1930.

WALTHER RICHTER.

pipe when deenergized, and means associated with each unit adapted to prevent vertical movement of the boom until said hook is completely engaged with or disengaged from the pipe.

4. In a crane for transporting pipe, a horizontal boom, an independent engaging and releasing unit at each endof the boom comprising a pivotally mounted hook, a solenoid, a core disposed axially of said solenoid, and a link directly connecting said hook to said core, the solenoid upon being energized effecting a release of the hook from pipe engaging position.

5. In a crane for transporting pipe, a horizontal boom, an independent engaging and releasing unit at each end of the boom comprising a hook pivotally mounted on said boom, a solenoid for eiectin release of said hook upon being energize a core disposed axially of said solenoid, a link directly connecting said hook to said core, and means associated with each of said units 

